8N bearing Issues

[MIKE ANDRASKO]

Thanks for all the help, the bearings rolled right out with the home-made nail tool.
In fact the one that was to be the hardest to get out all most fell out (the rear main).
Another issue I have is what size bearings to put back in?
I founded a machine shop stamp on the side of the crank shaft by the #1 main bearing journal in the front with a double 020 stamp over itself (not sure if the double stamp means anything), and another stamp above it by the piston rod journal stamped with a 030 one time (no double stamp here). I’m reading these stamps as .020” under on the mains, and .030” under on the piston rod bearing journals.
The first thing I did was to plastigauge the main bearings to see how much they had worn; front main was .008”, the middle was .006”, and the rear was .005”.
The main bearings that I removed were; Clevite, 2-89, 010, MB-947P, all three had the same stamp on them. I’m guessing that these are undersize by .010”.
The piston rod bearings that I removed were (#1 )Clevite 77, 989 CB 200 P, B, (#2 )Clevite 77, 989 CB 200 P, A1, (#3 )Clevite 77, 989 CB 200 P, A1, and (#4 )Clevite 77, 989 CB 200 P, A1. Now these I can’t make out what they are, the guy where I order my parts says He can’t cross the numbers to anything. Anyone know what this number means?
I measured the main bearings journals; front 2.228”, middle 2.228”, rear, I could not get to it being an in-chassis job. The piston rod bearing journals measured; (#1) 2.062”, (#2) 2.063”, (#3) 2.063”, and (#4) 2.062”.
With all the above information given, I would install .020” under size main bearings, and .030” under sized piston rod bearings.
It looks like the person who overhauled the engine put the wrong bearings in, or am I all very confused?
Can someone clear this up for me?
Thanks
Mike
P.S.The reason for doing the overhaul is the oil pump quit working, no oil pressure after about 20 minutes. What I found was the drive bushing had about .010 to .015” slop and the housing was undercut by a previous gear about .015”. It was clear to me that someone had rebuilt this oil pump without knowing it would never work right with the housing this bad.

 

[36 Coupe]

A good parts man will measure the thickness of the bearings to id their size.

 

[TheOldHokie]

(quoted from post at 22:43:27 04/08/12) Thanks for all the help, the bearings rolled right out with the home-made nail tool.
In fact the one that was to be the hardest to get out all most fell out (the rear main).
Another issue I have is what size bearings to put back in?
I founded a machine shop stamp on the side of the crank shaft by the #1 main bearing journal in the front with a double 020 stamp over itself (not sure if the double stamp means anything), and another stamp above it by the piston rod journal stamped with a 030 one time (no double stamp here). I’m reading these stamps as .020” under on the mains, and .030” under on the piston rod bearing journals.
The first thing I did was to plastigauge the main bearings to see how much they had worn; front main was .008”, the middle was .006”, and the rear was .005”.
The main bearings that I removed were; Clevite, 2-89, 010, MB-947P, all three had the same stamp on them. I’m guessing that these are undersize by .010”.
The piston rod bearings that I removed were (#1 )Clevite 77, 989 CB 200 P, B, (#2 )Clevite 77, 989 CB 200 P, A1, (#3 )Clevite 77, 989 CB 200 P, A1, and (#4 )Clevite 77, 989 CB 200 P, A1. Now these I can’t make out what they are, the guy where I order my parts says He can’t cross the numbers to anything. Anyone know what this number means?
I measured the main bearings journals; front 2.228”, middle 2.228”, rear, I could not get to it being an in-chassis job. The piston rod bearing journals measured; (#1) 2.062”, (#2) 2.063”, (#3) 2.063”, and (#4) 2.062”.
With all the above information given, I would install .020” under size main bearings, and .030” under sized piston rod bearings.
It looks like the person who overhauled the engine put the wrong bearings in, or am I all very confused?
Can someone clear this up for me?
Thanks
Mike
P.S.The reason for doing the overhaul is the oil pump quit working, no oil pressure after about 20 minutes. What I found was the drive bushing had about .010 to .015” slop and the housing was undercut by a previous gear about .015”. It was clear to me that someone had rebuilt this oil pump without knowing it would never work right with the housing this bad.

It would indeed appear the wrong main bearings were installed and not just size.

2.228 is .020 under on the mains:

MS-1706P is the Clevite part number for the main bearing [u:17a433ff62][b:17a433ff62]set[/b:17a433ff62][/u:17a433ff62]
MB-947P is the Clevite part number for the #1 and #3 main bearings
MB-948P is the Clevite part number for the #2 main bearing.

2.063 is .030 under on the crank pins:

CB-200P is the part number for the connecting rod brearing

Replacing the oil pump housing which is also the front main bearing cap requires line boring the block. I'm afraid your plans for an in-frame job will have to be upgraded to a full teardown and a trip to the shop for the block.

TOH

PS> This is why I cringe when someone says they have "just rebuilt" the engine in a tractor they have for sale....